Morphological brain changes associated with Schneider's first-rank symptoms in schizophrenia: a MRI study

Altered neural basis of self-reflective processing in schizophrenia: An fMRI study

BACKGROUND

Impaired self-awareness has often been described in schizophrenia. Recent neuroimaging studies examining the self-reflection processes in schizophrenia have produced inconsistent results.

METHOD

We examined the self-reflective neural network using self- and other-evaluation tasks in schizophrenia. Fifteen schizophrenia patients and fifteen age- and sex-matched healthy subjects underwent functional magnetic resonance imaging. Subjects were required to decide whether the sentence described their own personal trait (self-evaluation) and that of their close friends (other-evaluation).

RESULTS

Unlike normal control subjects, the schizophrenia patients did not have greater activation of the left posterior cingulate gyrus and hippocampus during self-evaluation than during other-evaluation. On the other hand, the schizophrenia patients had higher activation of the right superior frontal and right supramarginal gyri during self-evaluation than control subjects. Only the patient group exhibited hyperactivation in the left hippocampus and right external capsule associated with the other-evaluation task.

CONCLUSIONS

These findings provide evidence for an altered neural basis of self-reflective processing, which may underlie the self-awareness deficits in schizophrenia.

A systematic examination of brain volumetric abnormalities in recent-onset schizophrenia using voxel-based, surface-based and region-of-interest-based morphometric analyses

Background

Brain morphometric abnormalities in schizophrenia have been extensively reported in the literature. Whole-brain volumetric reductions are almost universally reported by most studies irrespective of the characteristics of the samples studied (e.g., chronic/recent-onset; medicated/neuroleptic-naïve etc.). However, the same cannot be said of the reported regional morphometric abnormalities in schizophrenia. While certain regional morphometric abnormalities are more frequently reported than others, there are no such abnormalities that are universally reported across studies. Variability of socio-demographic and clinical characteristics across study samples as well as technical and methodological issues related to acquisition and analyses of brain structural images may contribute to inconsistency of brain morphometric findings in schizophrenia. The objective of the present study therefore was to systematically examine brain morphometry in patients with recent-onset schizophrenia to find out if there are significant whole-brain or regional volumetric differences detectable at the appropriate significance threshold, after attempting to control for various confounding factors that could impact brain volumes.

Methods

Structural magnetic resonance images of 90 subjects (schizophrenia = 45; healthy subjects = 45) were acquired using a 3 Tesla magnet. Morphometric analyses were carried out following standard analyses pipelines of three most commonly used strategies, viz., whole-brain voxel-based morphometry, whole-brain surface-based morphometry, and between-group comparisons of regional volumes generated by automated segmentation and parcellation.

Results

In our sample of patients having recent-onset schizophrenia with limited neuroleptic exposure, there were no significant whole brain or regional brain morphometric abnormalities noted at the appropriate statistical significance thresholds with or without including age, gender and intracranial volume or total brain volume in the statistical analyses.

Conclusions

In the background of the conflicting findings in the literature, our findings indicate that brain morphometric abnormalities may not be directly related to the schizophrenia phenotype. Analysis of the reasons for the inconsistent results across studies as well as consideration of alternate sources of variability of brain morphology in schizophrenia such as epistatic and epigenetic mechanisms could perhaps advance our understanding of structural brain alterations in schizophrenia.

Electronic supplementary material

The online version of this article (doi:10.1186/s12952-015-0030-z) contains supplementary material, which is available to authorized users.

Evidence from structural and diffusion tensor imaging for frontotemporal deficits in psychometric schizotypy

BACKGROUND

Previous studies of nonclinical samples exhibiting schizotypal traits have provided support for the existence of a continuous distribution of psychotic symptoms in the general population. Few studies, however, have examined the neural correlates of psychometric schizotypy using structural and diffusion tensor imaging (DTI).

METHODS

Healthy volunteers between the ages of 18 and 68 were recruited from the community and assessed using the Schizotypal Personality Questionnaire and received structural and DTI exams. Participants with high (N = 67) and low (N = 71) psychometric schizotypy were compared on gray and white matter volume, and cortical thickness in frontal and temporal lobe regions and on fractional anisotropy (FA) within 5 association tracts traversing the frontal and temporal lobes.

RESULTS

Higher levels of schizotypy were associated with lower overall volumes of gray matter in both the frontal and temporal lobes and lower gray matter thickness in the temporal lobe. Regionally specific effects were evident in both white matter and gray matter volume of the rostral middle frontal cortex and gray matter volume in the pars orbitalis. Moreover, relative to individuals who scored low, those who scored high in schizotypy had lower FA in the inferior fronto-occipital fasciculus as well as greater asymmetry (right > left) in the uncinate fasciculus.

CONCLUSIONS

These findings are broadly consistent with recent data on the neurobiological correlates of psychometric schizotypy as well as findings in schizotypal personality disorder and schizophrenia and suggest that frontotemporal lobe dysfunction may represent a core component of the psychosis phenotype.

Structural MRI Differences between Patients with and without First Rank Symptoms: A Delusion?

OBJECTIVE

It has been suggested that specific psychotic symptom clusters may be explained by patterns of biological abnormalities. The presence of first rank symptoms (FRS) has been associated with cognitive abnormalities, e.g., deficits in self-monitoring or in the experience of agency, suggesting that a specific network of neural abnormalities might underlie FRS. Here, we investigate differences in cortical and subcortical brain volume between patients with and without FRS.

METHODS

Three independent patient samples (referred to as A, B, and C) with different mean ages and in different illness stages were included, leading to a total of 348 patients within the schizophrenia-spectrum. All underwent magnetic resonance imaging of the brain. In addition, the presence of FRS was established using a diagnostic interview. Patients with (FRS+, A: n = 63, B: n = 129, and C: n = 96) and without FRS (FRS-, A: n = 35, B: n = 17, and C: n = 8) were compared on global and local cortical volumes as well as subcortical volumes, using a whole brain (cerebrum) approach.

RESULTS

Nucleus accumbens volume was significantly smaller in FRS+ as compared with FRS- in sample A (p < 0.005). Furthermore, FRS+ showed a smaller volume of the pars-opercularis relative to FRS- in sample B (p < 0.001). No further significant differences were found in cortical and subcortical volumes between FRS+ and FRS- in either one of the three samples after correction for multiple comparison.

CONCLUSION

Brain volume differences between patients with and without FRS are, when present, subtle, and not consistent between three independent samples. Brain abnormalities related to FRS may be too subtle to become visible through structural brain imaging.

[Personalised medicine in psychiatry and psychotherapy. A review of the current state-of-the-art in the biomarker-based early recognition of psychoses]

The main goal of psychiatric high-risk research--the personalised early recognition and intervention of schizophrenic and affective psychoses--is one of the biggest challenges of current clinical psychiatry due to the immense socioeconomic burden of these disorders. In this regard, this review discusses the prospects and caveats of new clinical, neuropsychological, neurophysiological and imaging-based concepts aimed at optimising the current state-of-the-art of early recognition. Finally, multivariate modelling and machine learning methods are presented as a novel methodological framework facilitating the decoding of early psychosis into different intermediate phenotypes. In the future, these phenotypes could be employed for a more objective risk stratification that operates at the single-subject level. This could allow us to generate clinically applicable prognostic biomarkers for these disorders that would propel the individualised prevention of disease transition, chronification and psychopharmacological treatment resistance of psychotic disorders.

Disturbance of intentionality: a phenomenological study of body-affecting first-rank symptoms in schizophrenia

OBJECTIVES

In 1950, Kurt Schneider proposed that a considerable number of schizophrenia patients develop first-rank symptoms (FRS). In such cases, patients report made experiences, replaced control of will, thought insertion, broadcast or withdrawal and delusional perception, respectively. Although a number of recent studies tend to explain FRS in terms of neurobiological and neuropsychological processes, the origin of these symptoms still remains unknown. In this paper, we explore the subjective experience of patients with the following two FRS: (1) "made" impulses and (2) "made" volitional acts.

METHOD

The method applied for the study of two FRS consists first in the overview of psychiatric and philosophical literature and second in the further investigation of subjective experience in patients with FRS. Psychopathological and phenomenological aspects of FRS are discussed by means of patient cases.

RESULTS

We discovered a profound transformation of intentionality and agency in schizophrenia patients with body-affecting FRS. This concept offers an insight into the interrelatedness between particular FRS.

CONCLUSION

We propose that the subjective experience of schizophrenia patients with body-affecting FRS is rooted in the disturbance of intentionality and diminished sense of agency. This theoretical account of body-affecting FRS will open up new directions in both phenomenological and neurobiological psychiatric research.

Relationship between Brain-Derived Neurotrophic Factor and Schneiderian First Rank Symptoms in Antipsychotic-Naïve Schizophrenia

Neurodevelopmental aberrations influenced by neurotrophic factors are among the important paradigms to understand schizophrenia pathogenesis. Among various neurotrophic factors, Brain-Derived Neurotrophic Factor (BDNF) is strongly implicated by previous research studies. Evaluating co-morbidity free, antipsychotic-naïve schizophrenia patients for BDNF levels and examining the correlates of this factor with symptoms might facilitate elucidation of its pathogenetic role without confounds of potential influencing factors. In this study, 59 co-morbidity free, antipsychotic-naïve schizophrenia patients were compared with 60 healthy controls for serum BDNF levels. In addition, the relationship between Schneiderian First Rank Symptoms (FRS) and BDNF level in patients was examined. As a group, schizophrenia patients (28.8 ± 11.7 ng/mL) had significantly lower serum BDNF than healthy controls (34.9 ± 8.2 ng/mL) after controlling for the potential confounding effects of age and sex (F = 7.8; p = 0.006). Further analyses revealed FRS status to have significant effect on plasma BDNF after controlling for the potential confounding effects of age and sex (F = 4.5; p = 0.01). Follow-up post hoc analyses revealed FRS(+) patients to have significant deficit in plasma BDNF level in comparison with healthy controls (p = 0.002); however, FRS(-) patients did not differ from healthy controls (p = 0.38). Our study observations add further support to the role for BDNF in schizophrenia pathogenesis and suggest a potential novel link between deficient BDNF and FRS.

Amygdala-hippocampal shape and cortical thickness abnormalities in first-episode schizophrenia and mania

BACKGROUND

Abnormalities in cortical thickness and subcortical structures have been studied in schizophrenia but little is known about corresponding changes in mania and brain structural differences between these two psychiatric conditions, especially early in the stage of the illness. In this study we aimed to compare cortical thickness and shape of the amygdala-hippocampal complex in first-episode schizophrenia (FES) and mania (FEM). Method Structural magnetic resonance imaging (MRI) was performed on 28 FES patients, 28 FEM patients and 28 healthy control subjects who were matched for age, gender and handedness.

RESULTS

Overall, the shape of the amygdala was deformed in both patient groups, relative to controls. Compared to FEM patients, FES patients had significant inward shape deformation in the left hippocampal tail, right hippocampal body and a small region in the right amygdala. Cortical thinning was more widespread in FES patients, with significant differences found in the temporal brain regions when compared with FEM and controls.

CONCLUSIONS

Significant differences were observed between the two groups of patients with FES and FEM in terms of the hippocampal shape and cortical thickness in the temporal region, highlighting that distinguishable brain structural changes are present early in the course of schizophrenia and mania.

The development of psychotic disorders in adolescence: a potential role for hormones

This article is part of a Special Issue "Puberty and Adolescence". The notion that adolescence is characterized by dramatic changes in behavior, and often by emotional upheaval, is widespread and longstanding in popular western culture. In recent decades, this notion has gained increasing support from empirical research showing that the peri- and post-pubertal developmental stages are associated with a significant rise in the rate of psychiatric symptoms and syndromes. As a result, interest in adolescent development has burgeoned among researchers focused on the origins of schizophrenia and other psychotic disorders. Two factors have fueled this trend: 1) increasing evidence from longitudinal research that adolescence is the modal period for the emergence of "prodromal" manifestations, or precursors of psychotic symptoms, and 2) the rapidly accumulating scientific findings on brain structural and functional changes occurring during adolescence and young adulthood. Further, gonadal and adrenal hormones are beginning to play a more prominent role in conceptualizations of adolescent brain development, as well as in the origins of psychiatric symptoms during this period (Walker and Bollini, 2002; Walker et al., 2008). In this paper, we begin by providing an overview of the nature and course of psychotic disorders during adolescence/young adulthood. We then turn to the role of hormones in modulating normal brain development, and the potential role they might play in the abnormal brain changes that characterize youth at clinical high-risk (CHR) for psychosis. The activational and organizational effects of hormones are explored, with a focus on how hormone-induced changes might be linked with neuropathological processes in the emergence of psychosis.

Sex differences and structural brain maturation from childhood to early adulthood

Recent advances in structural brain imaging have demonstrated that brain development continues through childhood and adolescence. In the present cross-sectional study, structural MRI data from 442 typically developing individuals (range 8-30) were analyzed to examine and replicate the relationship between age, sex, brain volumes, cortical thickness and surface area. Our findings show differential patterns for subcortical and cortical areas. Analysis of subcortical volumes showed that putamen volume decreased with age and thalamus volume increased with age. Independent of age, males demonstrated larger amygdala and thalamus volumes compared to females. Cerebral white matter increased linearly with age, at a faster pace for females than males. Gray matter showed nonlinear decreases with age. Sex-by-age interactions were primarily found in lobar surface area measurements, with males demonstrating a larger cortical surface up to age 15, while cortical surface in females remained relatively stable with increasing age. The current findings replicate some, but not all prior reports on structural brain development, which calls for more studies with large samples, replications, and specific tests for brain structural changes. In addition, the results point toward an important role for sex differences in brain development, specifically during the heterogeneous developmental phase of puberty.

Dopaminergic foundations of schizotypy as measured by the German version of the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE)-a suitable endophenotype of schizophrenia

The concept of schizotypy or “psychosis proneness” captures individual differences in perceptual, cognitive, and affective experiences that may relate to a range of psychotic disorders. The concept is an important way to assess the contribution of pre-existing psychological and genetically based biological features to the development of illnesses such as schizophrenia (so called endophenotypes). The Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) is a widely used multi-dimensional measure of the construct and consists of four scales which mirror several groups of psychotic symptoms: Unusual Experiences (UnEx; positive symptoms), Cognitive Disorganization (CogDis; cognitive symptoms), Introvertive Anhedonia (IntAn; negative symptoms), and Impulsive Nonconformity (ImpNon; impulsive and antisocial symptoms). For the purpose of evaluating the suitability of schizotypy as an endophenotype of schizophrenia the current version of the O-LIFE was translated into German: its psychometric properties (including re-test reliability and construct validity) were examined in a large sample (n > 1200) and compared to those of the English original. The German version was both highly reliable and consistent with the original. The study aimed to show that schizotypy as measured by the O-LIFE can indeed be regarded as an endophenotype of schizophrenia in terms of genetic associations regarding relevant dopamine-related candidate polymorphisms of schizotypy [i.e., Val¹⁵⁸Met-polymorphism of the COMT gene, uVNTR of the MAOA gene, Taq1A-polymorphism of the DRD2 gene, VNTR of the SLC6A3 (DAT) gene]. We also wanted to compare the genetic associations of the O-LIFE to those published using other operationalizations of schizotypy. Our results show a large number of significant associations and borderline-significant trends between the O-LIFE sub-scales and a range of genes, thereby supporting using the O-LIFE in the search for endophenotypic markers.

Digit ratio (2D:4D) asymmetry and Schneiderian first rank symptoms: implications for cerebral lateralisation theories of schizophrenia

Schneiderian first rank symptoms (FRS) in schizophrenia have been hypothesised to be secondary to aberrant cerebral lateralisation over the course of human evolution. The ratio of length of second digit to fourth digit (2D:4D) has been put forward as a potential indicator of cerebral lateralisation. This study examined 2D:4D and its asymmetry in antipsychotic-naïve schizophrenia patients (N=79) in comparison with healthy controls (N=75). Psychopathology was assessed using Scales for Assessment of Positive and Negative Symptoms. FRS assessment was performed as per established descriptions. The digit lengths (2D & 4D) were measured using a digital vernier caliper with good inter-rater reliability. Female schizophrenia patients showed significantly lower 2D:4D than female healthy controls. Mean 2D:4D asymmetry index was significantly lower in male schizophrenia patients than male healthy controls. FRS status had significant effect on left 2D:4D as well as 2D:4D asymmetry index, the patients with FRS having the lowest values. Our study findings support association between schneiderian FRS and low 2D:4D as well as low 2D:4D asymmetry index. Since 2D:4D is linked with limbic asymmetry, our study findings offer further support to the cerebral lateralisation theories of schizophrenia.

Adolescents at ultra-high risk for psychosis with and without 22q11 deletion syndrome: a comparison of prodromal psychotic symptoms and general functioning

OBJECTIVE

Genetic syndromes related to psychosis have become increasingly important for exploring the trajectory that leads to psychosis onset. A very significant opportunity for mapping earlier phases of the trajectory can be found in 22q11.2 deletion syndrome (22q11DS). Comparative studies have shown that schizophrenic disorder in 22q11DS largely resembles schizophrenia in the general population, but only few studies have investigated the features of prodromal symptoms in 22q11DS. The aim of the present study was to investigate differences and similarities between two samples: patients with 22q11DS clinically at risk for psychotic onset (UHR+22q11DS group) and patients at clinical high risk for psychotic onset (UHR group).

METHOD

The study was conducted on a sample of 30 individuals UHR+22q11DS and 81 individuals at UHR without 22q11DS. The two groups were compared on positive, negative and depressive symptoms, level of general functioning and IQ.

RESULTS

There was a significant group difference in negative symptoms, but no significant differences were found for positive, global and total symptoms. The UHR+22q11DS group showed a lower level of general functioning. The clinical profile of the UHR+22q11DS group was clearly more homogeneous.

CONCLUSIONS

Even if the two UHR groups are comparable in terms of positive symptoms, the UHR+22q11DS have a specific clinical pattern characterized by higher negative symptoms, lower general functioning and an older age of onset of the UHR state. This finding may be of clinical value for the development of specific therapeutic intervention for UHR+22q11DS, and of theoretical value since the two groups may share only some underlying etiopathogenetic mechanisms.

Possible dysregulation of cortical plasticity in auditory verbal hallucinations-A cortical thickness study in schizophrenia

INTRODUCTION

Investigations of gray matter changes in relation with auditory verbal hallucinations (AVH) have reported conflicting results. Assuming that alterations in gray matter might be related to certain symptoms in schizophrenia this study aimed to investigate changes in cortical thickness specific to AVH. It was hypothesized that schizophrenia patients suffering from persistent AVH would show significant differences in cortical thickness in regions involved in language-production and perception when compared to schizophrenia patients which had never experienced any hallucinations.

METHODS

Using cortical thickness analysis the present study investigated ten schizophrenic patients suffering from AVH, ten non-hallucinating schizophrenic patients, and ten healthy control subjects. Anatomical data were acquired on a 3 T MRI system, transformed into standard space and cortically aligned to investigate local differences in whole brain cortical thickness between the two patient groups. Based on this comparison, brain regions with alterations specific for the patients with AVH were identified and then used as regions of interest to compare both patient groups to the healthy subjects respectively.

RESULTS

Hallucinating patients showed gray matter reductions in the dominant hemisphere predominantly in sensory language areas relevant for speech processing. Increased cortical thickness was found in regions related to self-monitoring.

CONCLUSIONS

Gray matter reductions in chronic schizophrenic patients may be the sequel of synaptic derangement or disease-related deregulation of language circuits. In order to clarify the ambiguous information processing additional demands might be put on cortical structures responsible for self-monitoring processes leading to changes in cortical thickness in the sense of neural plasticity.

Structural changes in the hippocampus and amygdala at first episode of psychosis

Hippocampus and amygdala changes have been implicated in the pathophysiology and symptomatology of both schizophrenia (SCZ) and bipolar disorder (BD). However relationships between illness course, neuropathological changes and variations in symptomatology remain unclear. This investigation examined the associations between hippocampus and amygdala volumes and symptom dimensions in schizophrenia and bipolar disorder patients after their first episode of psychosis. Symptom severity was associated with decreases in hippocampus/amygdala complex volume across groups. In keeping with previous work bilateral hippocampus and amygdala volume reductions were also identified in the SCZ patients while in BD patients only evidence of amygdala inflation reached significance. The study concludes that there appear to be important relationships between volume changes in the hippocampus and amygdala and dimensions and severity of symptomatology in psychosis. Structural alterations are apparent in both SCZ and BD after first episode of psychosis but present differently in each illness and are more severe in SCZ.

'Social dysmetria' in first-episode psychosis patients

OBJECTIVE

The 'embodied cognition' hypothesis suggests a close relationship between internal self-representations and the outward expression of social behaviours and emotions. Given self-awareness disturbances in patients with first-rank symptoms (FRS), we hypothesized that these patients would show abnormal social behaviours. In this study, we examined the social interactive skills of patients with first-episode psychosis during an interview, together with changes in performance over time.

METHOD

We analysed previously unreported data from 227 patients with first-episode psychosis (90 with, and 137 without, FRS) who took part in the WHO multicentre study on the Determinants of Outcome of Severe Mental Disorders. They were assessed on the Psychological Impairment Rating Schedule (PIRS) and examined again after 2 years.

RESULTS

A principal component analysis on the Psychosocial Impairment Rating Schedule produced two factors (interactive skills; withdrawal from interactions). Patients with FRS showed greater impairments in the domain linked to 'interactive skills', which remained 2 years after the first experience of a psychotic illness. These findings were not explained by clinical characteristics, or presence of non-FRS delusions.

CONCLUSION

Self-awareness deficits, as indexed by the FRS symptom cluster, are linked to deficits in social interactive behaviours. These abnormalities are indicative of 'social dysmetria' in this group, which involves difficulties conveying motor aspects of behaviours, volition and affect to facilitate mutual communication. These findings point to the utility of behavioural assessment scales in clinical and research settings.

Hippocampal volume reduction in first-episode and chronic schizophrenia: a review and meta-analysis

Several magnetic resonance imaging studies have reported hippocampal volume reduction in patients with schizophrenia, but other studies have reported contrasting results. In this review and meta-analysis, the authors aim to clarify whether a reduction in hippocampal volume characterizes patients with schizophrenia by considering illness phase (chronic and first episode) and hippocampus side separately. They made a detailed literature search for studies reporting physical volumetric hippocampal measures of patients with schizophrenia and healthy control (HC) participants and found 44 studies that were eligible for meta-analysis. Individual meta-analyses were also performed on 13 studies of first-episode patients and on 22 studies of chronic patients. The authors also detected any different findings when only males or both males and females were considered. Finally, additional meta-analyses and analyses of variance investigated the role of the factors "illness phase" and "side" on hippocampal volume reduction. Overall, the patient group showed significant bilateral hippocampal volume reduction compared with HC. Interestingly, first-episode and chronic patients showed same-size hippocampal volume reduction. Moreover, the left hippocampus was smaller than the right hippocampus in patients and HC. This review and meta-analysis raises the question about whether hippocampal volume reduction in schizophrenia is of neurodevelopmental origin. Future studies should specifically investigate this issue.

Schneiderian first rank symptoms and inferior parietal lobule cortical thickness in antipsychotic-naïve schizophrenia

Inferior parietal lobule (IPL) is implicated in the pathogenesis of first rank symptoms (FRS) in schizophrenia by functional neuroimaging studies. However, the relationship between IPL cortical thickness and FRS is yet to be explored. In this study, cortical thickness of IPL was analyzed in antipsychotic-naïve schizophrenia patients (total number = 51) with [FRS(+); N = 25] and those without FRS [FRS(-); N = 26] in comparison with group-matched healthy controls (N = 47). FRS(+) patients showed significant cortical thickness deficit in right IPL (specifically angular gyrus) in comparison with both FRS(-) patients (p = 0.005) and healthy controls (p = 0.0002); lack of difference on the left side might possibly be related to larger variance in healthy controls. Deficient cortical thickness involving IPL in FRS(+) schizophrenia patients adds further support to the role of internal monitoring system in the pathogenesis of FRS in schizophrenia.

Brain anatomical abnormalities in high-risk individuals, first-episode, and chronic schizophrenia: an activation likelihood estimation meta-analysis of illness progression

OBJECTIVE

The present study reviewed voxel-based morphometry (VBM) studies on high-risk individuals with schizophrenia, patients experiencing their first-episode schizophrenia (FES), and those with chronic schizophrenia. We predicted that gray matter abnormalities would show progressive changes, with most extensive abnormalities in the chronic group relative to FES and least in the high-risk group.

METHOD

Forty-one VBM studies were reviewed. Eight high-risk studies, 14 FES studies, and 19 chronic studies were analyzed using anatomical likelihood estimation meta-analysis.

RESULTS

Less gray matter in the high-risk group relative to controls was observed in anterior cingulate regions, left amygdala, and right insula. Lower gray matter volumes in FES compared with controls were also found in the anterior cingulate and right insula but not the amygdala. Lower gray matter volumes in the chronic group were most extensive, incorporating similar regions to those found in FES and high-risk groups but extending to superior temporal gyri, thalamus, posterior cingulate, and parahippocampal gryus. Subtraction analysis revealed less frontotemporal, striatal, and cerebellar gray matter in FES than the high-risk group; the high-risk group had less gray matter in left subcallosal gyrus, left amygdala, and left inferior frontal gyrus compared with FES. Subtraction analysis confirmed lower gray matter volumes through ventral-dorsal anterior cingulate, right insula, left amygdala and thalamus in chronic schizophrenia relative to FES.

CONCLUSIONS

Frontotemporal brain structural abnormalities are evident in nonpsychotic individuals at high risk of developing schizophrenia. The present meta-analysis indicates that these gray matter abnormalities become more extensive through first-episode and chronic illness. Thus, schizophrenia appears to be a progressive cortico-striato-thalamic loop disorder.

Schizotypy and brain structure: a voxel-based morphometry study

BACKGROUND

Schizotypy is conceptualized as a subclinical manifestation of the same underlying biological factors that give rise to schizophrenia and other schizophrenia spectrum disorders. Individuals with psychometric schizotypy (PS) experience subthreshold psychotic signs and can be psychometrically identified among the general population. Previous research using magnetic resonance imaging (MRI) has shown gray-matter volume (GMV) abnormalities in chronic schizophrenia, in subjects with an at-risk mental state (ARMS) and in individuals with schizotypal personality disorder (SPD). However, to date, no studies have investigated the neuroanatomical correlates of PS.

METHOD

Six hundred first- and second-year university students completed the Community Assessment of Psychic Experiences (CAPE), a self-report instrument on psychosis proneness measuring attenuated positive psychotic experiences. A total of 38 subjects with high and low PS were identified and subsequently scanned with MRI. Voxel-based morphometry (VBM) was applied to examine GMV differences between subjects with high and low positive PS.

RESULTS

Subjects with high positive PS showed larger global volumes compared to subjects with low PS, and larger regional volumes in the medial posterior cingulate cortex (PCC) and the precuneus. There were no regions where GMV was greater in low than in high positive PS subjects.

CONCLUSIONS

These regions, the PCC and precuneus, have also been sites of volumetric differences in MRI studies of ARMS subjects and schizophrenia, suggesting that psychotic or psychotic-like experiences may have common neuroanatomical correlates across schizophrenia spectrum disorders.

Anterior cingulum volumetry, auditory P300 in schizophrenia with negative symptoms

The anterior cingulate cortex (ACC) is located at the rostum of the corpus callosum and involved in both cognitive and emotional brain processes. It has been suggested to be involved in P300 event-related potential generation. A large sample of schizophrenia inpatients and controls was examined in order to assess the potential relationship between ACC volumes and P300 characteristics in patients with more pronounced negative symptoms. In 50 male schizophrenia patients and 50 matched controls, auditory P300 and structural magnetic resonance imaging volume measurements of the ACC were obtained. Patients' negative symptoms were assessed using the PANSS (Positive and Negative Syndrome Scale). Volumetry of ACC subregions revealed a volume reduction in patients with schizophrenia compared with controls in right hemispheric rostral ACC subregions that were most pronounced in more negative schizophrenia patients. There was a positive correlation between PZ P300 amplitude and total ACC volume in the right hemisphere in schizophrenia patients with less negative symptoms. The results support the assumption that structural changes of the ACC are more pronounced in subgroups of schizophrenia patients with more negative psychopathology. In addition, while right hemisphere ACC volumes significantly differ between schizophrenia subgroups, combining measures of event-related potential (ERP) and ACC volumetry does not add additional information.

The functional neuroanatomy of symptom dimensions in schizophrenia: a qualitative and quantitative review of a persistent question

One of the fundamental goals in understanding schizophrenia is linking the observable symptoms to the underlying unobservable pathophysiology. Given recent advances in medical imaging, researchers are increasingly investigating brain-behavior relationships to better understand the neural substrates of negative, positive, and disorganization symptoms in schizophrenia. This review focused on 25 task-related functional magnetic resonance imaging studies and found meaningful small to moderate associations between specific symptom dimensions and regional brain activity. Negative symptoms were related to the functioning of the ventrolateral prefrontal cortex and ventral striatum. Positive symptoms, particularly persecutory ideation, were related to functioning of the medial prefrontal cortex, amygdala, and hippocampus/parahippocampal region. Disorganization symptoms, although less frequently evaluated, were related to functioning of the dorsolateral prefrontal cortex. Surprisingly, no symptom domain had a consistent relationship with the middle or superior temporal regions. While a number of adaptations in experimental design and reporting standards can facilitate this work, current neuroimaging approaches appear to provide a number of consistent links between the manifest symptoms of schizophrenia and brain dysfunction.

Anatomical abnormalities of the anterior cingulate cortex in schizophrenia: bridging the gap between neuroimaging and neuropathology

The anterior cingulate cortex (ACC) is a functionally heterogeneous region involved in diverse cognitive and emotional processes that support goal-directed behaviour. Structural magnetic resonance imaging (MRI) and neuropathological findings over the past two decades have converged to suggest abnormalities in the region may represent a neurobiological basis for many of the clinical manifestations of schizophrenia. However, while each approach offers complimentary information that can provide clues regarding underlying patholophysiological processes, the findings from these 2 fields are seldom integrated. In this article, we review structural neuroimaging and neuropathological studies of the ACC, focusing on the unique information they provide. The available imaging data suggest grey matter reductions in the ACC precede psychosis onset in some categories of high-risk individuals, show sub-regional specificity, and may progress with illness duration. The available post-mortem findings indicate these imaging-related changes are accompanied by reductions in neuronal, synaptic, and dendritic density, as well as increased afferent input, suggesting the grey matter differences observed with MRI arise from alterations in both neuronal and non-neuronal tissue compartments. We discuss the potential mechanisms that might facilitate integration of these findings and consider strategies for future research.

Inferior parietal lobule volume and schneiderian first-rank symptoms in antipsychotic-naïve schizophrenia: a 3-tesla MRI study

BACKGROUND

As per Frith's neuro-cognitive model, inferior parietal lobule (IPL) is implicated in the pathogenesis of Schneiderian first-rank symptoms (FRS) in schizophrenia. The specific role of IPL structural abnormalities in the pathogenesis of FRS is yet to be ascertained.

MATERIALS AND METHODS

Using 3-tesla MRI scanner, this first-time study examined antipsychotic-naïve schizophrenia patients ( n = 28) (patients with FRS [FRS +]: N = 14, M: F = 7:7; and patients without FRS [FRS-]: N = 14, M: F = 7:7) in comparison with sex-, handedness-, education- and socioeconomic status-matched healthy controls (n = 14, M: F = 7:7). The volume of IPL was measured using a three-dimensional, interactive, semi-automated analysis, with good inter-rater reliability.

RESULTS

FRS + patients showed significant volume deficit in right IPL in comparison with healthy controls (F = 4.0; P=.028) after controlling for the potential confounding effects of age, sex and intracranial volume.

CONCLUSIONS

Right IPL volume deficit in FRS+patients adds further support to the Frith's model of FRS in schizophrenia.

The relationship between symptom severity and regional cortical and grey matter volumes in schizophrenia

OBJECTIVE

To investigate the relationship between symptom severity and cortical and grey matter volumes in schizophrenia.

METHOD

Fifty-three outpatients with schizophrenia were assessed by the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. Symptoms were grouped into five factors (negative, relational, inattention, disorganization, and reality distortion). Cortical and lobar grey matter volumes within all regions of the brain were obtained from magnetic resonance images using two independent software tools. The relationships between brain volumes and symptom factors were analyzed by partial correlations controlling for age, gender, dose and type of antipsychotic medication, and intracranial volume.

RESULTS

Negative symptoms were generally associated with larger cortical volumes in all regions of the brain, and the relational and inattention factors were associated with larger frontal grey matter volumes. The reality distortion factor was associated with smaller cortical volumes throughout the brain and with smaller frontal and temporal grey matter volumes.

CONCLUSION

Differential contribution of positive and negative symptoms to variation in cortical and grey matter volumes indicates separate neurobiological mechanisms underlying the two major symptom domains in schizophrenia.

Mapping grey matter reductions in schizophrenia: an anatomical likelihood estimation analysis of voxel-based morphometry studies

Voxel-based morphometry (VBM) is a popular tool for mapping neuroanatomical changes in schizophrenia patients. Several recent meta-analyses have identified the brain regions in which patients most consistently show grey matter reductions, although they have not examined whether such changes reflect differences in grey matter concentration (GMC) or grey matter volume (GMV). These measures assess different aspects of grey matter integrity, and may therefore reflect different pathological processes. In this study, we used the Anatomical Likelihood Estimation procedure to analyse significant differences reported in 37 VBM studies of schizophrenia patients, incorporating data from 1646 patients and 1690 controls, and compared the findings of studies using either GMC or GMV to index grey matter differences. Analysis of all studies combined indicated that grey matter reductions in a network of frontal, temporal, thalamic and striatal regions are among the most frequently reported in literature. GMC reductions were generally larger and more consistent than GMV reductions, and were more frequent in the insula, medial prefrontal, medial temporal and striatal regions. GMV reductions were more frequent in dorso-medial frontal cortex, and lateral and orbital frontal areas. These findings support the primacy of frontal, limbic, and subcortical dysfunction in the pathophysiology of schizophrenia, and suggest that the grey matter changes observed with MRI may not necessarily result from a unitary pathological process.

Voxel-based structural magnetic resonance imaging (MRI) study of patients with early onset schizophrenia

BACKGROUND

Investigation into the whole brain morphology of early onset schizophrenia (EOS) to date has been sparse. We studied the regional brain volumes in EOS patients, and the correlations between regional volume measures and symptom severity.

METHODS

A total of 18 EOS patients (onset under 16 years) and 18 controls matched for age, gender, parental socioeconomic status, and height were examined. Voxel-based morphometric analysis using the Brain Analysis Morphological Mapping (BAMM) software package was employed to explore alterations of the regional grey (GM) and white matter (WM) volumes in EOS patients. Symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

EOS patients had significantly reduced GM volume in the left parahippocampal, inferior frontal, and superior temporal gyri, compared with the controls. They also had less WM volume in the left posterior limb of the internal capsule and the left inferior longitudinal fasciculus. The positive symptom score of PANSS (higher values corresponding to more severe symptoms) was negatively related to GM volume in the bilateral posterior cingulate gyrus. The negative symptom score was positively correlated with GM volume in the right thalamus. As for the association with WM volume, the positive symptom score of PANSS was positively related to cerebellar WM (vermis region), and negatively correlated with WM in the brain stem (pons) and in the bilateral cerebellum (hemisphere region).

CONCLUSION

Our findings of regional volume alterations of GM and WM in EOS patients coincide with those of previous studies of adult onset schizophrenia patients. However, in brain regions that had no overall structural differences between EOS patients and controls (that is, the bilateral posterior cingulate gyrus, the right thalamus, the cerebellum, and the pons), within-subject analysis of EOS patients alone revealed that there were significant associations of the volume in these areas and the symptom severity. These findings suggest that at an early stage of the illness, especially for those with onset before brain maturation, a wide range of disturbed neural circuits, including these brain regions that show no apparent morphological changes, may contribute to the formation of the symptomatology.

Sexually dimorphic changes in the amygdala in relation to delusional beliefs in first episode psychosis

BACKGROUND

Few attempts have been made to examine the relationship between amygdala abnormalities and specific symptoms in psychosis. The present study explored the relationship between amygdala morphology and mood congruent and mood incongruent delusional beliefs.

METHODS

Amygdala volumes were measured in 43 patients presenting with delusional beliefs in the context of their first episode of psychosis and 43 healthy volunteers matched for age and gender.

RESULTS

Left-greater-than-right-asymmetry of the amygdala varied as a function of gender and mood congruence of delusional beliefs, due to asymmetrical enlargement of the left amygdala in women presenting with predominantly mood incongruent delusions. However, there was no difference in amygdala volumes across groups.

CONCLUSIONS

Amygdala abnormalities in women may be associated with aberrant emotional processing that could contribute to the development of mood incongruent delusional beliefs. Sexually dimorphic changes in the amygdala may contribute to differential phenotypic illness expression in men and women.

Anterior and posterior cingulum abnormalities and their association with psychopathology in schizophrenia: a diffusion tensor imaging study

Evidence suggests that a disruption in limbic system network integrity and, in particular, the cingulate gyrus may play a role in the pathophysiology of schizophrenia. The cingulum bundles (CBs; posterior and anterior) are the most prominent white matter tracts in the limbic system, furnishing both input and output to the cingulate gyrus . In previous diffusion tensor imaging (DTI) studies, abnormal integrity has been demonstrated in the anterior CB portion, but not the posterior, in schizophrenia. As well, the relationships between the abnormalities of CB integrity and the psychopathology of schizophrenia remain to be elucidated. Using DTI acquired on a 3 T MRI machine, we examined fractional anisotropy (FA) in the anterior and posterior CBs of 42 patients with schizophrenia and 24 group-matched controls. Moreover, we investigated the relationships between CB abnormalities and the psychopathology of schizophrenia. Bilaterally reduced FA was demonstrated in both anterior and posterior CBs in schizophrenia patients. However, the pattern of FA reduction was different between anterior and posterior CBs: the reduction in FA was left-accentuated in anterior CBs, while no such lateralized abnormality was found in posterior ones. Finally, FA in posterior CBs correlated with positive symptom scores in patients with schizophrenia. These findings suggest that CB abnormalities in schizophrenia are not restricted to the anterior CB, but include the posterior as well. Pathology in the posterior CB would be one of the possible neural underpinnings of positive symptoms in schizophrenia.

Reduced microstructural integrity of the white matter underlying anterior cingulate cortex is associated with increased saccadic latency in schizophrenia

The anterior cingulate cortex (ACC) is a key component of a network that directs both spatial attention and saccadic eye movements, which are tightly linked. Diffusion tensor imaging (DTI) has demonstrated reduced microstructural integrity of the anterior cingulum bundle as indexed by fractional anisotropy (FA) in schizophrenia, but the functional significance of these abnormalities is unclear. Using DTI, we examined the white matter underlying anterior cingulate cortex in schizophrenia to determine whether reduced FA is associated with prolonged latencies of volitional saccades. Seventeen chronic, medicated schizophrenia outpatients and nineteen healthy controls had high-resolution DTI scans. FA maps were registered to structural scans and mapped across participants using a surface-based coordinate system. Cingulate white matter was divided into rostral and dorsal anterior regions and a posterior region. Patients showed reduced FA in cingulate white matter of the right hemisphere. Reduced FA in the white matter underlying anterior cingulate cortex, frontal eye field, and posterior parietal cortex of the right hemisphere was associated with longer saccadic latencies in schizophrenia, though given the relatively small sample size, these relations warrant replication. These findings demonstrate that in schizophrenia, increased latency of volitional saccades is associated with reduced microstructural integrity of the white matter underlying key cortical components of a right-hemisphere dominant network for visuospatial attention and ocular motor control. Moreover, they suggest that anterior cingulate white matter abnormalities contribute to slower performance of volitional saccades and to inter-individual variability of saccadic latency in chronic, medicated schizophrenia.

Effect of prefrontal cortex inactivation on behavioral and neurochemical abnormalities in rats with excitotoxic lesions of the entorhinal cortex

Morphological studies report reductions in the volume of medial temporal lobe structures and the prefrontal cortex in subjects with schizophrenia. The present study was performed to clarify the role of prefrontal-temporo-limbic system in the manifestation of psychosis, using entorhinal cortical lesion rats as a vulnerability animal model. Quinolinic acid (lesion group) or phosphate buffer (sham group) was infused into the left entorhinal cortex (EC) of male Wistar rats. On the 28th postoperative day, methamphetamine (MAP; 1 mg/kg, i.p.)-induced dopamine (DA) release in the nucleus accumbens (NAC) and the basolateral amygdala (BLA), as well as locomotor activity and prepulse inhibition (PPI), was measured following microinfusion of lidocaine or the cerebrospinal fluid (CSF) into the medial prefrontal cortex (mPFC). Lesions of the EC resulted in enhancement of MAP-induced DA release in the NAC and BLA. Further analysis revealed that the enhancement by EC lesions of MAP-induce DA release in the NAC was particularly evident in the lidocaine-infused rats. EC lesions also enhanced MAP-induced locomotor activity, especially in the lidocaine-treated animals. By contrast, infusion of lidocaine into mPFC attenuated MAP-induced DA release in the BLA, irrespective of the lesion status. Both EC lesions and lidocaine infusion disrupted PPI. These results indicate that inactivation of the mPFC, as well as structural abnormalities in the EC, leads to dysregulation of DAergic neurotransmissions in the limbic regions. The implications of these findings in relation to the neural basis for psychosis vulnerability are discussed.

Volume reduction of the left planum temporale gray matter associated with long duration of untreated psychosis in schizophrenia: a preliminary report

A longer duration of untreated psychosis (DUP) in schizophrenia is reported to lead to a poorer clinical outcome, possibly reflecting a neurodegenerative process after the onset of overt psychosis. However, the effect of DUP on brain morphology in schizophrenia is still poorly understood. In this study, we used magnetic resonance imaging to investigate the relation between DUP and volumetric measurements for the superior temporal sub-regions (Heschl's gyrus, planum temporale, and caudal superior temporal gyrus), the medial temporal lobe structures (hippocampus and amygdala), and the frontal lobe regions (prefrontal area and anterior cingulate gyrus) in a sample of 38 schizophrenia patients (20 males and 18 females) whose illness duration was less than five years. We found a significant negative correlation between DUP and the volume of gray matter in the left planum temporale even after controlling for age, age at illness onset, and duration and dosage of neuroleptic medication. There was no such correlation for the other brain regions including each sub-region of the prefrontal cortex (the superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus, ventral medial prefrontal cortex, orbitofrontal cortex, and straight gyrus). When subjects were divided into two groups around the median DUP, the long-DUP group had a significantly smaller planum temporale gray matter than the short-DUP group. These findings may reflect a progressive pathological process in the gray matter of the left planum temporale during the initial untreated phase of schizophrenia, whereas abnormalities in the medial temporal regions might be, as has been suggested from previous longitudinal findings, relatively static at least during the early course of the illness.

Temporal lobe gray matter in schizophrenia spectrum: a volumetric MRI study of the fusiform gyrus, parahippocampal gyrus, and middle and inferior temporal gyri

Although several brain morphologic studies have suggested abnormalities in the temporal regions to be a common indicator of vulnerability for the schizophrenia spectrum, less attention has been paid to temporal lobe structures other than the superior temporal gyrus or the medial temporal region. In this study, we investigated the volume of gray matter in the fusiform gyrus, the parahippocampal gyrus, the middle temporal gyrus, and the inferior temporal gyrus using magnetic resonance imaging in 39 schizotypal disorder patients, 65 schizophrenia patients, and 72 age and gender matched healthy control subjects. The anterior fusiform gyrus was significantly smaller in the schizophrenia patients than the control subjects but not in the schizotypal disorder patients, while the volume reduction of the posterior fusiform gyrus was common to both disorders. Volumes for the middle and inferior temporal gyri or the parahippocampal gyrus did not differ between groups. These findings suggest that abnormalities in the posterior region of the fusiform gyrus are, as have been suggested for the superior temporal gyrus or the amygdala/hippocampus, prominent among the temporal lobe structures as a common morphologic substrate for the schizophrenia spectrum, whereas more widespread alterations involving the anterior region might be associated with the development of full-blown schizophrenia.

Differential contributions of prefrontal and temporolimbic pathology to mechanisms of psychosis

Common abnormalities within the schizophrenia spectrum may be essential for the pathogenesis of schizophrenia, but additional pathological changes may be required for the development of full-blown schizophrenia. Clarifying the neurobiological similarities and differences between established schizophrenia and a milder form of schizophrenia spectrum disorder would potentially discriminate the pathophysiological mechanisms underlying the core features of the schizophrenia spectrum from those associated with overt psychosis. High-resolution MRIs were acquired from 25 patients with schizotypal disorder, 53 patients with schizophrenia and 59 healthy volunteers matched for age, gender, handedness and parental education. Volumetric measurements of the medial temporal structures and the prefrontal cortex subcomponents were performed using consecutive 1-mm thick coronal slices. Parcellation of the prefrontal cortex into subcomponents was performed according to the intrinsic anatomical landmarks of the frontal sulci/gyri. Compared with the controls, the bilateral volumes of the amygdala and the hippocampus were reduced comparably in the schizotypal and schizophrenia patients. The parahippocampal gyrus volume did not differ significantly between diagnostic groups. Total prefrontal grey matter volumes were smaller bilaterally in the schizophrenia patients than in the controls and the schizotypal patients, whereas the schizotypal patients had larger prefrontal grey matter than the controls in the right hemisphere. In the schizophrenia patients, grey matter volumes of the bilateral superior frontal gyrus, left middle frontal gyrus, bilateral inferior frontal gyrus and bilateral straight gyrus were smaller than those in the controls. The schizophrenia patients also had reduced grey matter volumes in the right superior frontal gyrus, bilateral middle frontal gyrus and right inferior frontal gyrus relative to the schizotypal patients. Compared with the controls, the schizotypal patients had larger volumes of the bilateral middle frontal gyrus and smaller volumes of the right straight gyrus. There were no significant between-group differences in volumes of the ventral medial prefrontal cortex or the orbitofrontal cortex. These findings suggest that volume reductions in the amygdala and hippocampus are the common morphological substrates for the schizophrenia spectrum, which presumably represent the vulnerability. Additional widespread involvement of the prefrontal cortex in schizophrenia may lead to the loss of inhibitory control in other brain regions and suggests (although it is not specifically be related to) its critical role in the manifestation of overt psychosis.